An exhaust system for a vehicle may include a particulate filter. If the engine includes a diesel engine, then the particulate filter is referred to as a diesel particulate filter. The particulate filter traps particulate matter, i.e., soot, from the exhaust gas of the engine. The particulate filter may include one or more substrates that define a plurality of apertures, through which the exhaust gas must flow. The particulate matter collects on the substrate as the exhaust gas flows through the apertures. The particulate filter is occasionally regenerated to remove the collected particulate matter. Regeneration of the particulate filter includes heating the particulate filter to a temperature sufficient to burn the collected particulate matter, which converts the particulate matter to carbon dioxide that dissipates into the atmosphere.
A soot model may be employed to predict when the particulate filter is required to be regenerated. A pressure differential across the particulate filter, i.e., between an upstream end and a downstream end of the particulate filter, is one of the primary inputs into the soot model. The soot model predicts the necessity of regeneration based upon the pressure differential across the particulate filter or the time until regeneration is required. Auxiliary regeneration triggers, such as a pre-defined time between consecutive regenerations, a pre-defined distance traveled by the vehicle between consecutive regenerations, or pre-defined fuel consumption of the vehicle between consecutive regenerations may also be employed to start regeneration of the particulate filter. Accordingly, upon the occurrence of any of the auxiliary triggers, regeneration of the particulate filter may be started.